An oscillator generates an oscillating signal, e.g. an alternating current (AC), at a selected frequency. The frequency of the oscillating signal is typically locked to a reference frequency. Here, a so called voltage-controlled-oscillator may be used in connection with a phase lock loop. A phase lock loop is a control system that generates a control signal or a voltage Vtune, whose phase is related to the phase of an external reference signal. The phase lock loop compares the phase of the reference signal with the phase of the signal delivered from the oscillator and adjusts the frequency of same to keep the phases matched. The stable frequency of the reference signal is usually running at a much lower frequency compared to the frequency generated by the oscillator. Therefore, the frequency of the oscillator is down converted in order to be compared with the reference frequency. A typical application of such a phase locked oscillator is a transmitter configuration of a radar system or a communication device, wherein the oscillating signal may be modulated to generate a transmitter signal.